Xode project fails to compile a simple C++ class

Developer Tools & Services Xcode
ackh OP
Created Oct ’20
Replies 2
Boosts 0
Views 2.0k
Participants 2
I have a simple Xcode project that contains a single C++ class. However, when I attempt to build that project in Xcode I'm getting the following error message:

Code Block bash
error: unable to spawn process 
'/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang'
 (No such file or directory) (in target 'iOSStaticLibrary' from project 
'iOSStaticLibrary')

In addition, the following warning is emitted:

Code Block bash
warning: Could not read serialized diagnostics file: error("Failed to 
open diagnostics file") (in target 'iOSStaticLibrary' from project 
'iOSStaticLibrary')

I couldn't figure out how to attach the actual project to my post. It only consists of 3 files, so, I'm posting the relative filenames and contents below.

In order to recreate the problem, create the 3 files in the specified folder and add the corresponding content.

Code Block bash
File "ARM64/Debug/iOSStaticLibrary.xcodeproj/project.pbxproj":

Code Block plist
// !$*UTF8*$!
{
	archiveVersion = 1;
	classes = {
	};
	objectVersion = 46;
	objects = {
/* Begin PBXBuildFile section */
		3b051b2877334f3891e05fbf /* iOSStaticLibrary.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 810f8ddb516f4fd9aae95391 /* iOSStaticLibrary.cpp */; settings = {COMPILER_FLAGS = "-c -Wall -Wswitch -W\"no-deprecated-declarations\" -W\"empty-body\" -W\"bool-conversion\" -W\"constant-conversion\" -W\"shorten-64-to-32\" -W\"enum-conversion\" -W\"int-conversion\" -W\"return-type\" -Wparentheses -W\"no-pointer-sign\" -W\"no-format\" -Wuninitialized -W\"unreachable-code\" -W\"unused-function\" -W\"unused-value\" -W\"unused-variable\" -O0 -fno-strict-aliasing -fwritable-strings -fno-threadsafe-statics -fno-exceptions -std=gnu11 -x c"; }; };
/* End PBXBuildFile section */
/* Begin PBXFileReference section */
		0e5228c6fe3a40ef9446f1d3 /* libiOSStaticLibrary.a */ = {isa = PBXFileReference; explicitFileType = archive.ar; includeInIndex = 0; path = libiOSStaticLibrary.a; sourceTree = BUILT_PRODUCTS_DIR; };
		810f8ddb516f4fd9aae95391 /* iOSStaticLibrary.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; name = iOSStaticLibrary.cpp; path = ../../../iOSStaticLibrary.cpp; sourceTree = SOURCE_ROOT; };
/* End PBXFileReference section */
/* Begin PBXFrameworksBuildPhase section */
		c8f1fdfa1a1a4cf2af0a7098 /* Frameworks */ = {
			isa = PBXFrameworksBuildPhase;
			buildActionMask = 2147483647;
			files = (
			);
			runOnlyForDeploymentPostprocessing = 0;
		};
/* End PBXFrameworksBuildPhase section */
/* Begin PBXGroup section */
		20adea7cddb14f79ab5df50b /* Products */ = {
			isa = PBXGroup;
			children = (
				0e5228c6fe3a40ef9446f1d3 /* libiOSStaticLibrary.a */,
			);
			name = Products;
			sourceTree = SOURCE_ROOT;
		};
		cb87a76375d04d85a8368aa7 = {
			isa = PBXGroup;
			children = (
				810f8ddb516f4fd9aae95391 /* iOSStaticLibrary.cpp */,
				20adea7cddb14f79ab5df50b /* Products */,
			);
			sourceTree = "\"<group>\"";
		};
/* End PBXGroup section */
/* Begin PBXNativeTarget section */
		3488e49fcf514802b7be61b6 /* iOSStaticLibrary */ = {
			isa = PBXNativeTarget;
			buildConfigurationList = 67256f7dc92b42baa13ec8d3 /* Build configuration list for PBXNativeTarget "iOSStaticLibrary" */;
			buildPhases = (
				7baf7bfde3004dd493908ddd /* Sources */,
				c8f1fdfa1a1a4cf2af0a7098 /* Frameworks */,
			);
			buildRules = (
			);
			dependencies = (
			);
			name = iOSStaticLibrary;
			productName = iOSStaticLibrary;
			productReference = 0e5228c6fe3a40ef9446f1d3 /* libiOSStaticLibrary.a */;
			productType = "com.apple.product-type.library.static";
		};
/* End PBXNativeTarget section */
/* Begin PBXProject section */
		ee73158d3505468a8fdc43b9 /* Project object */ = {
			isa = PBXProject;
			attributes = {
				LastUpgradeCheck = 0610;
				ORGANIZATIONNAME = MyOrganizationName;
				TargetAttributes = {
					3488e49fcf514802b7be61b6 = {
						CreatedOnToolsVersion = 6.1;
					};
				};
			};
			buildConfigurationList = 33fd7959eb644d189bbaa7f7 /* Build configuration list for PBXProject "iOSStaticLibrary" */;
			compatibilityVersion = "Xcode 3.2";
			developmentRegion = English;
			hasScannedForEncodings = 0;
			knownRegions = (
				English,
				en,
			);
			mainGroup = cb87a76375d04d85a8368aa7;
			productRefGroup = 20adea7cddb14f79ab5df50b /* Products */;
			projectDirPath = "\n\n        ";
			projectRoot = "\n\n        ";
			targets = (
				3488e49fcf514802b7be61b6 /* iOSStaticLibrary */,
			);
		};
/* End PBXProject section */
/* Begin PBXSourcesBuildPhase section */
		7baf7bfde3004dd493908ddd /* Sources */ = {
			isa = PBXSourcesBuildPhase;
			buildActionMask = 2147483647;
			files = (
				3b051b2877334f3891e05fbf /* iOSStaticLibrary.cpp in Sources */,
			);
			runOnlyForDeploymentPostprocessing = 0;
		};
/* End PBXSourcesBuildPhase section */
/* Begin XCBuildConfiguration section */
		1cbb1a8c7cbf4c2699369b65 /* Debug */ = {
			isa = XCBuildConfiguration;
			buildSettings = {
			};
			name = Debug;
		};
		fda96981947c4c2cb659f3e3 /* Debug */ = {
			isa = XCBuildConfiguration;
			buildSettings = {
				CLANG_CXX_LIBRARY = "libc++";
				IPHONEOS_DEPLOYMENT_TARGET = 8.1;
				ONLY_ACTIVE_ARCH = YES;
				PRODUCT_NAME = "$(TARGET_NAME)";
				SDKROOT = iphoneos;
				SKIP_INSTALL = YES;
			};
			name = Debug;
		};
/* End XCBuildConfiguration section */
/* Begin XCConfigurationList section */
		33fd7959eb644d189bbaa7f7 /* Build configuration list for PBXProject "iOSStaticLibrary" */ = {
			isa = XCConfigurationList;
			buildConfigurations = (
				1cbb1a8c7cbf4c2699369b65 /* Debug */,
			);
			defaultConfigurationIsVisible = 0;
			defaultConfigurationName = Debug;
		};
		67256f7dc92b42baa13ec8d3 /* Build configuration list for PBXNativeTarget "iOSStaticLibrary" */ = {
			isa = XCConfigurationList;
			buildConfigurations = (
				fda96981947c4c2cb659f3e3 /* Debug */,
			);
			defaultConfigurationIsVisible = 0;
			defaultConfigurationName = Debug;
		};
/* End XCConfigurationList section */
	};
	rootObject = ee73158d3505468a8fdc43b9 /* Project object */;
}

Code Block bash
File "iOSStaticLibrary.h"

Code Block C++
class iOSStaticLibrary
{
public:
    iOSStaticLibrary();
    ~iOSStaticLibrary();
};

Code Block bash
File "iOSStaticLibrary.cpp":


Code Block C++
#include "iOSStaticLibrary.h"
iOSStaticLibrary::iOSStaticLibrary()
{
}
iOSStaticLibrary::~iOSStaticLibrary()
{
}


My assumption is that something in the project.pbxproj is not as it should be. This file is generated by a code generator, not by Xcode itself so that might well be the case.

However, for the life of me I cannot figure out what's wrong.
Answered by ackh in 639243022
Alright, I found the issue. The code generator creates the Xcode project as an XML file. If I open it in Xcode and apply a change to it, Xcode automatically converts the file to the other non-XML file format (i.e. as shown in the question).

Now, the code generator emits the following problematic code:
Code Block xml
        ...
        <key>projectDirPath</key>
        <string>
        </string>
        ...
        <key>projectRoot</key>
        <string>
        </string>
        ..

Both keys ("projectDirPath" / "projectRoot") should have an empty string as value and it actually does look like it is empty in the above XML.

However, Xcode interprets it differently. If the XML file is converted to the other format it looks as follows:
Code Block bash
...
projectDirPath = "\n\n        ";
projectRoot = "\n\n        ";
...

So, Xcode interprets the whitespace between <string> and </string> as actual value. To fix it, the code generator must be adjusted to emit
Code Block xml
        ...
        <key>projectDirPath</key>
        <string></string>
        ...
        <key>projectRoot</key>
        <string></string>
        ...

or <string /> or any other valid way instead of the above approach. That actually fixes the problem.

Replies  2
Boosts  0
Views  2.0k
Participants  2
szymczyk OP
Oct ’20
List the steps you took to create the project and add the files to it.

What type of project did you create? If you create a new project of a similar type and Xcode and run it, do you run into similar issues?
0
ackh OP
Oct ’20
Accepted Answer
Alright, I found the issue. The code generator creates the Xcode project as an XML file. If I open it in Xcode and apply a change to it, Xcode automatically converts the file to the other non-XML file format (i.e. as shown in the question).

Now, the code generator emits the following problematic code:
Code Block xml
        ...
        <key>projectDirPath</key>
        <string>
        </string>
        ...
        <key>projectRoot</key>
        <string>
        </string>
        ..

Both keys ("projectDirPath" / "projectRoot") should have an empty string as value and it actually does look like it is empty in the above XML.

However, Xcode interprets it differently. If the XML file is converted to the other format it looks as follows:
Code Block bash
...
projectDirPath = "\n\n        ";
projectRoot = "\n\n        ";
...

So, Xcode interprets the whitespace between <string> and </string> as actual value. To fix it, the code generator must be adjusted to emit
Code Block xml
        ...
        <key>projectDirPath</key>
        <string></string>
        ...
        <key>projectRoot</key>
        <string></string>
        ...

or <string /> or any other valid way instead of the above approach. That actually fixes the problem.

0
Xode project fails to compile a simple C++ class
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